notify

Overview ¶

Package notify performs a passive, never-blocking "you're behind" check for a Go CLI and prints a one-line hint when a newer GitHub release exists.

The hint is served from a small cache file - an instant disk read, never the network - so it adds no latency to the command. When that cache is stale, a background goroutine refreshes it; the refresh is never awaited, so it overlaps the caller's work and is abandoned at process exit if still running. The flush re-reads the cache, so a refresh that finishes while the command runs is shown that same run; otherwise its result appears on the next invocation. A tool describes itself with a brew.Config - the same value its self-update uses - calls Check before dispatching its command, and invokes the returned flush function after:

flush := notify.Check(brew.Config{
	Info:    clive.Info{Module: "github.com/me/myapp"},
	Formula: "myapp",
})
defer flush()

The check is silenced by the per-tool kill switch MYAPP_NO_UPDATE_CHECK (derived from the binary name) and by a non-terminal stderr, and the network is touched at most once per cooldown.

By default "latest" is the highest semver tag in the tool's GitHub repository. A tool whose releases are not readable GitHub tags - a private repo, or one distributed from an artifact bucket - overrides the lookup with WithLatestFunc while keeping the same cache, cooldown, and output.